The New York State Department of Health 1.2 MV high-voltage microscope facility is offered as a Northeastern regional facility for up to 50% of its time. Users will be assisted by members of the Electron Optics Laboratory in areas of thick-section cytology, stereoscopy, stereology, cytochemistry, and autoradiography. Electron microscopy and electron diffraction of wet materials (cells, membranes, viruses, and crystals) are made possible by an environmental chamber on the HVEM. A core research program will develop a highly accurate, axis-centered tilt stage for tomography. Elemental analysis by x-ray microprobe and energy-loss spectrometry will be developed for the HVEM on health-related problems (asbestosis, air-and water-borne particulates, deposits in tissues), frozen sections, as well as on wet whole cells. High-resolution dark field will employ electro rotating hollow-cone illumination. Low-dose microscopy using sensitive emulsions and a displaced beam, and a sensitive TV system will also be developed. Modifications of the HVEM including vibration-free pumping, (ion pumps and cryogenic traps), 40 degree K anticontaminator, and electronic changes, enable 4 angstrom point-to-point resolution to be obtained. Further improvements in resolution are expected. A User's Committee will review projects. Travel assistance for users is requested. Staff, equipment, and supplies are requested to scale up the present one-shift operation to two shifts.